Electromagnetic selector device



May l2y 1931.` c. w. soMr-:RsGALE ET Al.v 1,805,021

ELECTROMAGNETIC SELECTOR DEVICE Y A Filed May 7. 192s yiti Patented May12, 1931 UNITED s'rlrras PATENT omer:

, CHARLES vvILLIAJiI` soimnsenn AND JOHN ANDREW BELILE, or MONTEVIDEO, Ir o URUGUAY ELECTROMAGNETIC SELECTOR DEVICE Application filed Hay 7,1928, Serial No. 275,806, and in Great Britain December 7, 1927.

`This invention comprises a radial selector which consists of a numberof electro-inagnets corresponding to the number of kfunctions to beoperated arranged in such a manner that their poles are equidistant froma common armature which is suspended or so held as to enable it to havethe freedom of movement necessary to assure the required operation onits being attracted by any one electro-magnet.

`On any one magnet being energized, the armature is attracted andretainedl so long as the energizing current is applied and if duringthisperiod any other magnet or magnets in the system be energized, theattraction or resultant attraction thereof is insufficient to dislocatethe armature since the attractive force to which the armature issubjected by the magnet to which it has been drawn is greater than theforce or resultant of the total forces to" which it is subjected by theenergization of any one or more of the other magnets in the system.f,This is due to the fact that the armature is at a greater distancefromthe poles of the other magnets ythan it is from the one by which itwas attracted in the firstv instance'and further vto the fundamental lawthat the attractive force varies inversely as the square of thedistance.

The attraction of the ball or equivalent by any one magnet is made usevof to operate a 'contacter bank of contacts for the making and breakingoflocal or other circuits the device being then purely and simply aselective relay with certain inherent peculiari ties.

It is possible to employ the device to perform some function other thanthe operation of contacts, thus the basic principle may be expressed asfollows o Any number ofelectro-magnets are placed in such relation to acommon armature as to enable any one of the said magnets to attract thesaid armature and to retain it so long as the energizing current beapplied, with a magnetic attraction greater than thatto which it issubjected by the subsequent concomitant energization of any other magnetin the system or resultant attraction of any combination thereof, thusproviding an electrically per plated to avoid rust and preventphysioperated selective device for the making and breaking of circuitsor for other functions.

An embodiment -of the invention is illustrated in the accompanyingdrawings in which: y

Fig. 1 is a side elevation.

' Fig. 2 a plan view.

Fig. 3 a vertical section.

- Figli a section on line 4.-4 of Fig. 3.

The device is shown as adapted to operate a plurality of pairs ofcontacts a, b, eight pairs being shown in the drawings, there beingprovidedpfor each pair of contacts: an electromagnet c, mounted betweentwo frame members d, e the cores c1 of said magnets being 05 secured tothe base member l and projecting upwardly through the member e to acapping plate f. The member e is provided with a concave or dishedsurface e1 in which an armature, in the form of a ball g, normallyrests, the concave surface being such that said armature Will havefreedom of movement-in the direction ofthe energized magnet and themagnets being so arranged that their poles are equidistant from saidarmature in its nor.- mal position.

A ring h is interposed between the frame member e and the cappingplate-f and is provided with inwardly directed shoulders or abutmentsh1, the shoulders being equally spaced between the cores of the magnetsin such' a mannerthat when the armature is attracted by any one of thesaid magnets, it

'abuts against the adjacent shoulders, the armature being thus preventedfrom contacting 5 with any other magnet, as shown in Figs. 2 and 4. l

The contacts a, b are conveniently mounted on the base member d as bymeans of screws d1, the inner one of each of said pairs of contactsbeing provided at its upper endwith an inwardlydirected pin or the likeb1 passing through a hole 02 in the core c1 of eachmagnet and uponenergization of'one of the magnets, the respective pin is engaged by thearmature g to close the circuit between contacts a and b. c

The ball or equivalent should be of soft iron of high permeability andshould be copelectro-magnet.

cal contact of iron to iron which is Vundesirable in allelectro-magnetic devices where a small amount of residual magnetism canbe a disadvantage. Y

One of the uses for which this device is suitable isin anintercommunication telephone system` wherein each instrument lis fittedwith one of these selectors having vas many `ymagnetsas there areinstruments in the system lesstone.

On ringing up any subscriber in the system by means of a mechanicalstick button the battery current is applied to one coil of the callers,and onecoil of the called, instrument. It isonly necessary for thereceiver to be removed from the latter instrument to establishcommunication. Owing tothe principles-mentioned any other stationscalling those which are :thus in communication are unable to interfereor establish communication therewith .since although they are able toenergize. the coils of the relays in the instrument calledv -they areunable to attract thearmature and their-lines remain dead. until theprevious communication is terminated and the electro-magnetsdefenergized bythe replacementof the receivers.

-With this device the system can of course be elaborated to provideallthe additional indicationsof. special combinationssometimes furnished inapparatus of this v.type for specialreasons. n f

What we claim as our invention and desire to secure by Letters Patent ofthe United States is.:--.,.- Y

l. AnA electro-magnetic ,selector device comprising incombination aplurality of in.- dependently energizable electro-magnets,

not less than three,disposed in aV circle about -acommoncentreanarmature, and means for normally holding said armature at said.functions to be operated,a common armavturein 'theform of a ball,meanswhereby the said armature'is normallyfheld` equidistant from saidmagnets when the latter are not energized said armature having freedomof "movement in the direction ,of an. energized electro-magnet. f Y I3.1An 'electro-magnetic selector device comprising in combination, anumberof elec-y tro-magnets corresponding to thenumber of functions tobeoperated,a common armature 4in the formof a ball', al concave surfaceupon which said,I armature` is normally held equidistant'from'A saidVmagnets whenthe latter are not energized and allowed freedom ofvmovement necessary to assure .the required operation in the directionof an energized 4. An electro-magnetic selector device comprising incombination a number of electro-magnets corresponding to the number offunctions to be operated, a common armature, means whereby the saidarmature is rnormally held equidistant from said magnets when the latterare notenergized said farmature having freedom of movement in thedirection of any energized electro-magnet, and

abutments interposed between the cores of said magnets to ensurecontactof the armature with only one of the cores.

5. An electro-magnetic selector device comprising in combination, `anumber of pairs of contacts, a number of electro-magnets correspondingthereto, an inwardly extending pin on the inner of'each pair ofcontacts, the core of eachmagnet having ai hole for the passage ofsaidpin and acomm'on armature which upon attraction by the core of any ofthe vmagnets operates the contacts corre-` spending to said magnet.

. 6. An electro-magnetic selector device comprising in combination anumber of vpairs of cont-acts, a number of electro-magnets correspondingthereto, a common armature in the `form of a ball, means whereby thesaid armature is normally held equidistant from said magnets ywhen thelatter are not Aenergized, an inwardly extending'pin on the each magnethaving a holefor the passage of said pin andsaid armature uponattractionby kthe core of an energized magnet enf the pair of contactscorresponding to said magnet.V e l .f f 7. An electroemagnetic selectordevice comprisingin combination a number of pairs of contacts, a numberof `electromagnets corresponding thereto, a common armature in the formlof a ball, a member having a concave surface upon which said armatureisnormally held equidistant from said magnets when the latter are` notenergized and yallowed freedom of movement in the directionl of anenergized magnet, an `inwardly extending pinjon the inner of each pairof contacts, thecoreofeach magnet havnga hole for `the .passage of saidpm', said armature upon attraction by the core of an energized magnet.engaging the pineto ,close the circuit between the pairs ofcontactscorresponding to said magnet. n

8. An 'electro-magnetic selector device comprising in combination `afnumber of pairs of contactsa number OfelectrO-magnets correspondingthereto, a common armatureI in theformof a ball, a member having aconcave surface upon which said armature is normally held equidistantfrom said magnets when thelatter are not energized'and allowed `freedomof movement inthe direction ofan energized 1nagnet,"abutments interposedbetween the cores of'said magnets,

)5 inner ofi each pair of contacts,f.the core. of

gaging the pin to yclose the circuit between 10 izo an inwardlyextending pin on the inner of each pair of contacts, the core of eachmagnet having a hole for the passage of said pin, said armature uponattraction by the core of an energized ma et engaging the pin to closethe circuit etween the pairs of contacts corresponding to said magnet.

In Witness whereof we have signed this specification. CHARLES WILLIAMSOMERSGALE. JOHN ANDREW BELILE.

